To obtain a book cover in which both rear and front surfaces can be used by reversely folding both ends of the cover.

Both the ends of a book cover are folded inside, bagged and a cover is inserted. In this case, both the ends are reversibly bagged to provide a reversible book cover, and the intermediate part is formed longer than the conventional book cover. In the case of using, the cover is inserted to the right side, folded at this side, and the rear cover is wound to coat the cover. Thus, the book cover in which both the rear and front surfaces of the cover can be used is obtained, the design can be replaced by the atmosphere of the book, and in the case of contamination, the other surface can be used.